A downhole electric motor for a submersible pump has at least three phases and comprises a permanent magnet rotor and a stator bearing phase windings A, B and C in slots (2206) in the stator. Each phase winding A, B, C incorporates a coil extending through a respective pair of adjacent stator slots (2206) and surrounds a respective portion of the stator between the slots (2206). Furthermore adjacent coils of each pair of phase windings A, B, C extend through opposite parts of a respective one of the slots (2206), so that these coils extend alongside one another in the slot, either being separated by a gap through which cooling fluid may be pumped to cool the coils, or being separated by a thermally conductive projection (3110), with which the coils are in thermal contact, extending at least part of the way across the slot. Such a winding arrangement is advantageous in ensuring that the motor has a long life.